86 lines
2.4 KiB
JavaScript
86 lines
2.4 KiB
JavaScript
import { types as t, template } from "@babel/core";
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const buildForAwait = template(`
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async function wrapper() {
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var ITERATOR_COMPLETION = true;
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var ITERATOR_HAD_ERROR_KEY = false;
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var ITERATOR_ERROR_KEY;
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try {
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for (
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var ITERATOR_KEY = GET_ITERATOR(OBJECT), STEP_KEY, STEP_VALUE;
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(
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STEP_KEY = await ITERATOR_KEY.next(),
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ITERATOR_COMPLETION = STEP_KEY.done,
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STEP_VALUE = await STEP_KEY.value,
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!ITERATOR_COMPLETION
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);
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ITERATOR_COMPLETION = true) {
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}
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} catch (err) {
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ITERATOR_HAD_ERROR_KEY = true;
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ITERATOR_ERROR_KEY = err;
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} finally {
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try {
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if (!ITERATOR_COMPLETION && ITERATOR_KEY.return != null) {
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await ITERATOR_KEY.return();
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}
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} finally {
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if (ITERATOR_HAD_ERROR_KEY) {
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throw ITERATOR_ERROR_KEY;
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}
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}
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}
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}
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`);
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export default function (path, { getAsyncIterator }) {
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const { node, scope, parent } = path;
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const stepKey = scope.generateUidIdentifier("step");
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const stepValue = scope.generateUidIdentifier("value");
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const left = node.left;
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let declar;
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if (t.isIdentifier(left) || t.isPattern(left) || t.isMemberExpression(left)) {
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// for await (i of test), for await ({ i } of test)
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declar = t.expressionStatement(
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t.assignmentExpression("=", left, stepValue),
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);
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} else if (t.isVariableDeclaration(left)) {
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// for await (let i of test)
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declar = t.variableDeclaration(left.kind, [
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t.variableDeclarator(left.declarations[0].id, stepValue),
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]);
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}
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let template = buildForAwait({
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ITERATOR_HAD_ERROR_KEY: scope.generateUidIdentifier("didIteratorError"),
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ITERATOR_COMPLETION: scope.generateUidIdentifier(
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"iteratorNormalCompletion",
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),
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ITERATOR_ERROR_KEY: scope.generateUidIdentifier("iteratorError"),
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ITERATOR_KEY: scope.generateUidIdentifier("iterator"),
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GET_ITERATOR: getAsyncIterator,
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OBJECT: node.right,
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STEP_VALUE: t.cloneNode(stepValue),
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STEP_KEY: stepKey,
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});
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// remove async function wrapper
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template = template.body.body;
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const isLabeledParent = t.isLabeledStatement(parent);
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const tryBody = template[3].block.body;
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const loop = tryBody[0];
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if (isLabeledParent) {
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tryBody[0] = t.labeledStatement(parent.label, loop);
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}
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return {
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replaceParent: isLabeledParent,
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node: template,
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declar,
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loop,
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};
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}
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